Fact Sheet

Pepper flavour in

Please find attached signed

T&C form. If .

there is anything Background the population are blind to rotundone, unable to perceive it even at very high levels. There are only a few major flavour else that we can compounds in wine that come directly from When looking beyond wine, AWRI researchers the berry. One of the most important to were the first to recognise rotundone as the wine flavour is the ‘pepper’ compound impact aromato compound sign in peppercornsor you rotundone, which was identified in wine (Piper nigrum) and to identify it in many relatively recently. culinary herbs. Current work, in collaboration withneed CSIRO, involves before mapping the to Rotundone in wine assess spatial differences in rotundone, and seeks to increase understanding of AWRI researchers originally pinpointed environmental factors affecting its formation. rotundone as the cause of black or white 24/12, please let pepper flavour in Shiraz , developed an Rotundone in the analytical method to quantify it, and determined its potency. Rotundone has one While Shiraz is the mainme red wineknow. variety of the lowest detection thresholds of any where high concentrations of rotundone have aroma compound, meaning that only a tiny been found, other varieties such as , amount (around 16 ng/L) is required to give a Graciano, Duras and can have peppery character in . This is substantial levels. It is generally not an equivalent to a few drops in an Olympic-sized important flavour compound in Cabernet swimming pool. Interestingly, around 25% of Sauvignon, or grapes, or most white varieties. Rotundone is most

Updated February 2019

Fact Sheet WINEMAKING

prevalent in grapes from vineyards in cooler little affected by yeast. It remains at a regions and in cooler seasons, with cool constant level during post-fermentation growing conditions from to processes and is largely unchanged in bottled likely to be important. There can be more wine over extended ageing periods. than a 40-fold difference in rotundone between seasons for the same vineyard. Acknowledgement Typically, later harvested grapes have a much This work is supported by 's higher concentration than earlier picked grapegrowers and winemakers through their grapes. investment body Wine Australia, with In Shiraz berries rotundone has been found matching funds from the Australian almost entirely in grape skins rather than in Government. The AWRI is a member of the the pulp or seeds. Sun exposure on bunches Wine Innovation Cluster. is a major influence reducing the level of Further reading rotundone. Shaded bunches, and berries on Please find shaded parts of bunches or from less Wood, C., Siebert, T. E., Parker, M., Capone, D. exposed rows, have the highest levels. Leaf L., Elsey, G. M.; Pollnitz, A. P.;Eggers, M., Meier, removal around the bunch zone, especially at M., attachedVössing, T., Widder, S., Krammer, signed G., veraison, has a major effect on lowering Sefton, M. A., Herderich, M. J. 2008. From wine rotundone concentration. Vine water status to pepper: rotundone, an obscure also has an effect, with wetter conditions sesquiterpene,T&C is a potent form.spicy aroma If enhancing its concentration in berries. compound. J. Agric. Food Chem. 56 (10), 3738- 3744. Large differences within vineyards have been there is anything found, with considerable spatial variation, Bramley, R.G.V., Siebert, T.E., Herderich, M.J., which can be stable across seasons Krstic, M.P. 2017. Patterns of within-vineyard depending on the site. Selective harvesting spatialelse variation that in the ‘pepper’ we compound can could be an option to separate sections of rotundone are temporally stable from year to vineyards with higher and lower rotundone, year. Aust. J. Grape Wine Res. 23(1): 42-47 with blending of to adjust the level of to sign or you pepperiness then possible. Rotundone can be Contact easily tasted in berries, but winemakers For further information, please contact should ensure that they are not part of the need before the Markus Herderich. population who are blind to this character. Effects due to winemaking Phone24/12, 08 8313 6600 please let Email [email protected] Winemaking has only a small effect on rotundone, with extraction during Website me know. fermentation on skins being the critical step. https://www.awri.com.au/research_and_devel The techniques of extended and opment/2017-2025-rde-plan-projects/project- pre-ferment maceration have only a marginal 4-4-4/ effect, if any. style wines have dramatically lower rotundone concentrations Address Wine Innovation Central Building, than equivalent wines fermented on skins. Corner of Hartley Grove & Paratoo Rd, Rotundone is a very stable compound and is Urrbrae (Adelaide), SA 5064

Updated February 2019